122 km E of Chignik, Alaska

Yes. A magnitude 5.1 earthquake was recorded 122 km E of Chignik, Alaska at 08:37 UTC on 2022-09-20, 27 km deep.

2022-09-20 08:37 UTC · 27 km deep · released about 670 tons of TNT

Distance rings around the epicentre, with the nearest towns at their true direction and later quakes as coloured dots. Not a shaking map — see the USGS ShakeMap for that.

When: 2022-09-20 08:37 UTC
Magnitude: M 5.1 (mww)
Depth: 27 km below the surface
Felt: no reports yet
Measured shaking: intensity III (ShakeMap)
Tsunami: USGS flagged this event for tsunami evaluation. Follow tsunami.gov for official messages.
Status: Reviewed by a seismologist

USGS · last changed by USGS 1448 days ago · we first saw it 1448 days ago

This was a moderate earthquake. Shaking at this size can damage poorly built structures close to the epicentre.

At this magnitude and depth, people at rest would likely notice it out to about 204 km (127 mi) from the epicentre. Estimated from magnitude, depth and distance with the intensity equation USGS Did You Feel It? uses; felt reports, where there are any, are the measurement.

How big was it?

This earthquake released about 670 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 6.1 would have released about 32 times as much.

Northridge, California 1994 M 6.7 250× the energy of this one
Mineral, Virginia 2011 M 5.8 11× the energy of this one
Magna, Utah 2020 M 5.7 7.9× the energy of this one
This earthquake M 5.1 about 670 tons of TNT
Around the size people start to feel M 3.0 this one released 1,400× more

Energy from the Gutenberg–Richter relation (log₁₀E = 1.5M + 4.8), rounded to two figures; bar length is magnitude, which is already a logarithm of energy. Magnitudes of past earthquakes from the USGS catalogue.

For this area

The largest earthquake within 50 km since 2016 was M 6.9 on 2021-10-11 — about 500 times the energy of this one.

Before 2016, the USGS record lists 12 earthquakes of M5 or more within 50 km; the five largest:

7.0 113 km ESE of Chignik, Alaska · 38 km SSW of this epicentre May 4, 1923
6.9 143 km ESE of Chignik, Alaska · 38 km SSE of this epicentre Feb 13, 1951
6.4 77 km ESE of Chignik, Alaska · 46 km W of this epicentre Mar 24, 1972
6.3 112 km E of Chignik, Alaska · 12 km WNW of this epicentre Feb 25, 1953
6.1 132 km E of Chignik, Alaska · 13 km NE of this epicentre Sep 13, 1911

Since 2016: the QuakeIndex catalogue (US, M1.5+), built from the USGS FDSN event service. Before 2016: USGS ComCat, M5+ from 1900. Distances are between epicentres. This is the record, not a forecast.

Where

Map loads when it scrolls into view

Aftershocks so far

59 earthquakes have been recorded within 50 km since this one.

3.1 116 km E of Chignik, Alaska 07:48 UTC
2.2 111 km E of Chignik, Alaska 03:14 UTC
2.5 119 km E of Chignik, Alaska 05:24 UTC
2.3 89 km E of Chignik, Alaska 10:15 UTC
2.7 116 km E of Chignik, Alaska 09:07 UTC
2.3 130 km SSE of Ugashik, Alaska 06:50 UTC
2.8 96 km E of Chignik, Alaska 10:46 UTC
2.4 145 km E of Chignik, Alaska 16:09 UTC
2.2 119 km SSE of Ugashik, Alaska 15:50 UTC
3.0 129 km SSE of Ugashik, Alaska 12:39 UTC
2.3 110 km E of Chignik, Alaska 20:23 UTC
2.1 117 km E of Chignik, Alaska 12:47 UTC
2.2 129 km E of Chignik, Alaska 01:00 UTC
2.0 128 km E of Chignik, Alaska 16:01 UTC
2.0 117 km ESE of Chignik, Alaska 10:43 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 13:23 UTC. QuakeIndex does not forecast aftershocks. When USGS issues an operational aftershock forecast it appears on the USGS event page.

On USGS

The official USGS event page — the source of record for every value above
Did you feel it? Report it to USGS — reports go to USGS, not to us
ShakeMap for this event, when USGS has produced one

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.